Supercharged two-cycle engine



July 29, 1941.

L. N. MILLER 2,250,492

SUPERCHARGED Two-CYCLE ENGINE' Filed oct. 12, 1939 llIlIll/IIIIIIIIIIII/ Patented July 29, 1941 UNlTED STATES PATENT oFFlcEj 2,250,492 SUPERCHRGED TWO-CYCLE ENGINE Lauritz N. Miller, Eugene, Oreg. Application October 12, 1939, Serial No. 299,095

, 4 Claims.

This invention relates to a 2-cycle engine which may be of the internal combustion type utilizing gasoline or kindred fuels or which may be ofthe type using crude oil, fuel oil, and the ke, in that event being comparable to the sofcalled Diesel engine. p 2' f- The basic principles of the invention, however, lf 14are such that the engine will operate on other fuels, such as synthetic fuels, and the like,

lwherein said fuels in burning,y expand gaseously for useful work, the force of such expansion bevthe generation o'f an expanding gas, or gases,

for the derivation of power therefrom by reason of such expansion.

Since the internal combustion engine is almost universally understood as to operation and construction, the presentinvention is shown incorporated in an embodiment adapted for utilizing liquid fuel and morev especially .of the gasoline type. By the term "gasoline however, it is not to be understood that other vaporiz'ablefuids are excluded and as will hereinafter be pointed out, the invention is easily applicable to the utilization ofheavier liquid fuels, commonly employed in' Diesel engines, by substituting a fuel supply of the aforesaid character for the conventional carburetor or vaporizer utilized in the socalled gasoline engine.

'I'he chief object of the invention is to'prol vide an engine wherein a 2-cycle forml of operation isl utilized but which is modified so that substantially all the advantages of fi-'cycle operation are'obtainable therefrom.

The chief feature of the inventionconsists in the provision of a fuel receiving cylinder, a piston therein; an exhaust arrangement at one 4 end, an intake arrangement at the opposite end, and valve means associated with each arrangement and controlling exhaust from the 'said cylinder and fuel supply to said cylinder, the piston being of a control valve type, as hereinafter more fully pointed out. l

Other objects and features of the invention will be pointed out more fully hereinafter.

The full nature of the invention will be underfollowing description and claims:

In the drawing, Fig. 1 is a central sectional view of one emstood from the accompanying drawing and the bodiment of the invention showing the same as' an overhead type engine of gasoline fuel consuming character and air cooled.

Fig. 1A is a view of one of the counterba'land cheeks, of which two are provided, for the thxuwl portion of the crankshaft.

Fig. 2 is a sectional view of the 'intake valve operating arrangement.

Fig..3 is a similar view of the exhaust valve l operating arrangement.

Fig: 4 is a sectional view of lthe upper por-tion.v

of another embodiment of the invention showing the same as of L-head type and of water-cooled type.

In Fig. 1 vof the drawing there is illustrated a crankcase structure i0 which may be suitably supported. in any desirable manner. herein the same being shown provided with a base bracket arrangement Il. The desired number oi'bracket arrangements may be employed or may be otherwise positioned, it being understood, of course,

l the engine is primarily supported through the The lower end yof the` crankcase structure. I crankcase is provided with a conventional Adrain arrangement I2.

Mounted in the upper portion of vthe crankv case is a guide arrangement i3 which is relatively elongated and to which reference will be had more fully hereinafter. Herein the same is shown as ofcylinder type but it is not necessarily restricted thereto but may be a way structure. Slidably supported therein is a crosshead I or guide member I8 and the same mounts a wrist pin l5, in turn pivotally supporting one end of 1 a connecting rod i6. 4

'Ihe opposite end of the connecting rod projects beyond the lower open end i3d of the cylindrical guide arrangement and is pivotally connected 'as at I1 to a walking beam arrangement I8. This walking beam arrangement at its opposite end is pivotally connected as at i9 to a link structure 20, in turn pivotally mounted as at 2|. The walking beam is also pivotally mounted as at 22, intermediate and approximately midway between pivots Il and i9, on the throw or eccentric portion 23 of a crank shaft 24 and the cheeks 25 of said crankshaft are extended as at 26 opposite themthrow portion '23 and constitute a cdunterbalance arra gement, thus providing` for dynamic balancing of the shaft.

It is to be noted that this link.connecting rod,

-This communication walking beam and crankshaft construction is illustrated and described in the prior Miller Patent No. 2,005,000'and no claim specific thereto is made herein. The aforementioned patent discloses that the pivot, equivalent to pivot 2i, is of eccentric type and adjustable or variable. it also discloses but does not illustrate that this pivot may be .of fixed axis character.

Herein pivot Ei is of fixed axis type 'but it is to be expressly understood that ii desired, an

eccentric arrangement, as illustrated in theaforesaid patent,

combustion engine of the gasoline type and then being transformed to a Diesel type engine utilizing heavier fuels and operating compression ratio,'it being obvious that by shifting this axis the zero volume of the engine arrangement will be varied resulting in different compression ratios suitable for operation on different fuels and of the different types disclosed. This featureis mentioned herein but not claimed because it is disclosedgand claimed in the aforesaid application. It is mentioned herein to point out specifically the possible variations in adaptation of the invention proper herein disclosed and claimed, and such application is specifically made apart of this application insofar as the variable axis and adjustable compression ratio changes are concerned.

In substantially all .il-cycle engines, it is customary to utilize the crankcase as a part of the engine intake system. The present invention specifically differs therefrom in that--see Fig. 1the crankcase is sealed, as it were, from the cylinder structure, hereinafter to be described. Such seal is indicated bythe numeral 30 in Fig. land such seal is split and press-fitted into the remote or exposed end of the cylindrical guidearrangement. It is provided, however, with the bore 3i which slidably supports a. stem 32 at its lower end rigidly connected or integral with the crosshead arrangement I4.

In Fig. 1, the numeral illustrates a cylinder which, being of air cooled type, is provided with heat radiating fins 34. The lower end of this cylinder arrangement is provided with an enveloping intake chamber arrangement I5 communicating atregular or any other desired intervals by means of ports 36 with the lower end of the cylinder. 'Ihese ports are. however, positioned slightly remote from the extreme end of the cylinder for a purpose hereinafter to be described.

The chamber 35 is extended as at |38 and the same communicates with apassage 31 herein shown formed in and as a part of the crankcase although it need not necessarily `be so formed.

between chamber 38 and intake passage 31 is .controlled by an intake valve 38 of poppet valve type, having the stern 39 slidably supported in the guide 40. said stem carrying a spring retainer 4l with which is associated a pair of springs 42 and 43. This valve stem may on a greater be suitably actuated at the proper time to open the valve and provide free communication between chamber 35 and the intake passage 31, the valve being' positively closed and held closed by the said springs.

Reference now will be had to Fig. 2 wherein a conventional form of valve lift or operating mechanism is illustrated. Herein the numeral iid indicates a cam member or portion which is adapted to cooperate with a valve lifter sleeve it slidably Ysupported in a guide arrangement G6 in the crankcase structure. The sleeve G5 includes an extension 45a. against which bears the depending end of the valve stem 39.

As shown in Fig. l, the intake valve stern is aligned with the crankshaft axis and accordingly, if desired, this intake valve may be actuated by a cam on the crankshaft. This is the simpiest form and is readily adapted to single cylinder engine construction. For multiple cylinder engine construction, as is the practice and it is so intended herein to utilize a separate cam shaft for the several intake valves in preference to providing the crankshaft with a plurality of the intake valve operating cam portions. However, it is to be noted that contrary to the ii-cycle engine construction conventional today in automotive engines wherein the cam shaft operates at half crankshaft speed, this crankshaft of necessity must operate at crankshaft speed.

While the invention herein has been illustrated as embodying a poppet valve control for the intake chamber arrangement, it is to be understood that other valve type controls may be employed in lieu thereof and any valve arrangement operable cyclically, as herein disclosed, may be substituted and utilized without departing from the broader features of the invention.

The upper end of the cylinder 33 is closed in a conventional manner by a detachable head structure indicated generally by the numeral 41. It includes therein'an exhaust arrangement or chamber 48 and an exhaust passage 49. These two communicate and such communication is controlled by suitable valve means herein illustrated as'of poppet valve character and indicated by the numeral 5U. The poppet valve includes .the stern 5| and the same carries a retainer 52 with which is associated the springs 53 and 54 interposed vbetween the head and such retainer and normally constraining the exhaust valve to closed position. This exhaust valve herein is shown as of rocker arm operable type, the head supporting a bracket 55 which pivotally supports at 56 a rocker arm 51, the latter being actuated by a push-rod SB-see Figs. 1 and 3.

The push rod 58 is constructed somewhat similar to the valve lifter shown in Fig. 2. It is also operated by a cam 59. As shown in Fig. 1, the push rod 5B is offset slightly from the axis of the crankshaft. However, it is to be understood that the rocker arm structure may be so arranged that the push rod intersects the axis of the crankshaft and a cam thereon, such as indicated at 59, will operate said push rod to tilt the rocker arm clockwise in Fig. 1 in opposition to the springs 53 and 54 to open the exhaust valve at the proper time.

As previously set forth, any other valve suitable for the purpose may be. substituted for the aforesaid poppet valve and any other drive arrangement as previously set forth, may be utilized, it being noted in multiple cylinder constructions a single camshaft separate from the crankshaft is take and exhaust valve spaced for the desired timing.

camshaft would have crankshaft.

. i i, Le utilized and provided with the cams for the incylinder properly 'Herein such a the same speed as the s of each All the advantages ofmultiple cylinder and 2- cycle engine practice are well known insfar as overlapping power impulses are concerned. \It is, of course, to be understood that an engine of this character is provided with a flywheel arrangement. This conventional element, however, for simplicity has been intentionally omitted from the drawing. Since this is an air cooled engine, the head structure also is finned as at 60 for heat dissipation or cooling purposes.

Within the cylinder 33 is a piston structure Si provided with suitable rings t2 conventional to internal combustion engines. number and type of said rings may The piston is provided with a stem Any desired be employed.

32, before 2d mentioned, and said stem may be rigid with, as hereinillustrated. or integral with. as herein illustrated, the said piston. and is slidable in theseal connected, as stated, to the crosshead ld or guide This stem is elongated means Se. It is rigidly member slidable in the guide arrangement I3 in the crackcase it. The.

piston, as will be noted from Fig. 1, is of relatively" short length compared herent in the struction heretofore, t said piston. 'I'he same inder is such that the to automotive engine pistons and more especially to so-called 2cycle engine pistons, it being lnconventional 2-cycle engine cono provide a long skirt on herein is unnecessary.

the position of the intake end of the cylpiston 6l when at the end of the power stroke may completely uncover said l ports and provide free communication between the intake arrangement andthe cylinder on the i power side of the pisto It is to be observed of the block including the intake arrangementor chamber communicates with the lower and intake end of the cylinder on the b communication being 62 n. also that the construction the cylinder, is such that |36 freely ottom of the indicated by piston, this the numeral tis also to be noted-see Fig. l-and indicated" by numeral 63, the lower of sloping character the dotted line in turn indicated by the end of the chamber 35 is and insures -surplus fuel drainage to the intake valve port or seat.- This is to prevent iiooding.A herein shown provided ber and, therefore,

chamber is-indicated by the numeral closed by a plug stru is of hollow character.

The stem structure 32 is with an elongated cham- The 64 and is herein is cture 65 which /shown positioned in the head of the piston and it may have any desired exterior,as desired, and

found .suitable to facilitate combustion, swirling of the gases, et cetera, Vcombustion engine art.

well known inthe internal Within this chamber there is provided the de.

sired amountof material, the same being indicated by the numeralGB and representing a mixture of lithium nitrate and potassium nitrate.-

While this is introduce d as a powder, under heat the same becomes a liquid and the purpose thereof is to insure cooling of this stem and the piston,

that the it being understood entire chamber. 0n the same does not fill the i'lring stroke of the pislton when there is the greatest heat on the working face of the pistorr, is at theupper end of t due to inertiathis liquid his chamber and abstracts eration.

45, l`ports 36 and as long as such beyond the intake port sealing heat from the piston and carries it downwardly out hereinafter this lower portion of Athe ber and as will be pointed heat in transferred to the stem and there dissipated. 'I'here is provided alsoin the head,` as india spark plug B8. This may be otherwise positioned v as desired or required. It is, however, exposed in the zero volume portion of the combustion chamber and is arranged so that piston movement does not interfere with its ep- Since this invention hasbeen illustrated las applied to a gasoline engine, the numeral t9 indicates a conventional carburetor, the conve tional controls thereof being intentionally omitted and this carburetor is supplied with fuel from the reservoir it or any other suitable source of fuel conventional to gasoline engine practice.

In the preferred form' oi the invention, the vstem 32 is rigid with the piston and guide member. It may, however, be -otherwise connected thereto as by a member which is pivotally connected at opposite ends to vthe piston and the guide member. If desired, such last mentioned pivotal connection may be coaxial with the connecting rod connection for simplicity, thereby requiringbut a single wrist pin arrangement at the guide connection. At thispoint, the operation will be briefly set forth.

If a combustible charge is assumed to be in the exhaust. chamber and zero volume arrangement, the exhaust valve 56 being closed, and the piston being at the end of its compression stroke, the. plug 68 is energized to ignite the combustible mixtureV if the fuel is of thatcharacter. If the fuel be not of that character, a preheating plug for oil engine operation might be utilized or if the fuel is of the high pressurecharacter, common to Diesel engine practice, the fuel would ignite spontaneously when the piston reaches'the upper end of its compression stroke. Upon the fuel igniting, burning and expanding, the piston moves downwardly for work purposes. As the pistonA` moves down, it compresses the fuel in the intake chamber arrangement until the piston seals the seal is ailected. compression is continued because as illustrated by the dotted lines in Fig. l, the piston continues position. The exhaust valve is so timed that either prior tothe sealing or theunsealing of the intake ports,.t he zero volume chamber of the exhaust arrangement d8 is in free communication with the exhaust pipe or conduit 49 and these burned gases being under considerable pressure and passage 49 being substantially at atmospheric pressure, the gases im-N mediately discharge.I Y,

If the exhaust valve timing is such that it open fora shortI interval while the intakel ports 36 are open to the cylinder, then a scavenging eect is obtained by the incoming compressed intake charge. If, however, the exhaust valve is closedjprior. to the opening of the intake ports to. the cylinder by continued downward piston movement, there will be no scaveng'ing effect, and, therefore, no dilution of the incoming charge. When the ports 36 are uncovered, it is lquite apparent the compressed charge in the intake arrangement rushes into the cylinder and fills the same with a combustible mixture'. The piston upon cutting oil` these intake ports in the upward or return stroke, thereupon compresses this fuel charge until at or near the end of the is then ignited and the cycle is repeated.

compression stroke. It

The intake valve-38 is so timed as to operation that immediately upon the piston on its so-called return or compression stroke unsealing the ports 36, the valve is opened and the combustible mixture is supplied from the intake passage 31 to the intake chamber 35. It passes into the cylinder behind the non-Working face of the piston through the ports 36 and through the communication 62, and thus abstracts heat from the stem 32 and from the piston and from the cylinder wall, thus being preheated during this stage. Upon the compressed charge of fuel being fired, ignited, et cetera, and the piston returning Von its working stroke, this preheated, subsequent fuel charge is compressed as the piston approaches the intake ports 36, it being understood the intake valve 39 preferably is closed immediately prior to the initiation of the return stroke of the piston.

It also will be noted that 4on precompression of the subsequent charge that such pressure is supplementary to Ithe springs 42 and 43 for seating and maintaining the intake valve in seated relation. It also will be noted that during the compression and the working strokes, the compressing expanding gases are imposed on the exhaust valve and supplementing the springs 53 and 54 to maintain the exhaust valve in closedseated relation. Thus, the pressures produced in the engine are supplemental and not complemental or opposed to the valve springs, thereby insuring longer valve spring life.

It will be understood, of course, as has been previously suggested hereinbefore, that the Stroke of the piston can be regulated and, therefore,

the timing with relation to the intake ports for scavenging and degree scavenging can be readily obtained as well as thereof or the absence of A the ability to rapidly transform the engine from a gasoline to a Diesel type with a different compression ratio.

In Fig. 4 a modified form of the invention is illustrated and it is merely supplied to illustrate the adaptation of the major or basic presentations of the present invention to an L-type engine and the water-cooled type engine. In said Fig. 4, the valve stem is indicated by the numeral |5I, piston by the numeral IBI, the cylinder by the numeral |33, the head by the numeral |01, the type having the water jacketrportion |60. The

- exhaust passage is indicated by the numeral |49,

same being of water-cooled the exhaust valve herein is shown in inverted relation but still of poppet valve type and is indicated by the numeral |50, the stern |5| thereof being normally constrained to valve seated position by the spring |53 retained by the retainer |52 on said stem. The exhaust chamber arrangement |48 is in the head and the communication between |48 and |49 is by Way of the valve |50. The cylinder is Water jacketed as at |34. The operation o f this form oi the invention is identicalv to that previously described for the engine illustrated in Fig. 1.

Reference now will be had to Fig. 1 wherein there is illustrated an addition feature. Herein the link 20 pivoted at 2| is shown provided with an offset portion |20 and the link is relieved as at |2|. 'I'he crankcase is provided with a guide arrangement |00 and slidably mounted therein is an operating member |0| which may be or may not be provided with a spring for constraining it to proper position. The lower end of said member |0l is enlarged into substantially spherical form as at is seated in a socket portionv |03 provided ln the enlargement |20' of thelink 20. In the reciprocation of the piston it will be remembered the walking beam oscillates resulting in oscillation of the link 20 and this oscillation naturally secures reciprocation of the member |0|.

This reciprocation of said member may be employed for either of two purposes, to-wit, it may actuate a Diesel engine injector release arrangement for supplying Diesel engine fuel to the passage 31, or it may be injected into the combustion chamber 48 through a delivery nozzle such as is commonly used in Diesel engine operation. If the engine be of gasoline engine type, this actuating member |0| may be utilized to insure proper timing of the ignition and operation thereof.

While the invention has been illustrated and described in great detail in the drawing and foregoing description, the same is to be considered as illustrative and not restrictive in character.

The. several modifications described hereinas well asy others which will readily suggest themselves to persons skilled in this art, all arev considered to be within the broad scope of the invention, reference being had to the appended claims.

The invention claimed is:

1. In an internal combustion engine, the combination with a cylinder, a piston reciprocable therein, a connecting rod operatively connected at one end to the piston, a crankshaft, a walking beam carried thereby and connected at one end tothe rod for crankshaft movement, a link connected at one end to the other end` of the beam and pivotally supported at the opposite end, and means movable by and with the link movement for engine operation control.

2. In an air cooled engine, the combination with a cylinder having external iins thereon, an exhaust at one end, and an intake adjacent the opposite end, of a skirt type piston in the cylinder, a stem rigid therewith and a closure for the intake end ofthe cylinder and slidably supporting said stem, said closure including a cylinder directed enlargement forming an elongated bearing for the stern, and nesting in the skirted portion of the piston, the intake including a plurality of ports adjacent the closure end of the cylinder. a chamber thereabout and independent of the cylinder and freely communicating with the cylinder through the ports for cylinder charging and cylinder and piston cooling when the piston is at the intake end of the cylinder and for cylinder and piston cooling and combustible mixture intake for subsequent pre-compression when the piston is at the exhaust end of the cylinder.

, 3. In an internal combustion engine, a cylinder, a power piston therein, an elongated stem or rod rigid therewith and having an elongated chamber therein, and heat transferring fluid means in said.

chamber and movable from end to end thereof in |02 and the same 75 piston movement for piston cooling, the-combination of a connecting rod, a crankshaft, a walking beam intermediately carried by the'crank portion thereof and connected at one end to the rod, a guide arrangement in alignment with the cylinder, an elongated stem rigid with the piston, guide means in said guide arrangement and carried by the stem, the connecting rod having pivotal connection with the guide means, and a link pivoted at one end upon a stationary axis and at its opposte end to the other end of the walking beam for the purpose set forth.

4. In an internal combustion engine, a cylinder, a power piston therein, an rigid therewith and having an elongated chamber therein, heat transferring uid means in said chamber and movable from end to end thereof in piston movement for 'piston cooling, the combination of a connecting rod, ing beam intermediately carried by the crank portioh thereof and connected at one end to the rod, a guide arrangement in alignment with the cylinder, an elongated stem rigid with the piston, guide means in said guide arrangement and carried by elongated stem or rod .ating as a gasoline and the stem, the connecting rod having pivotal co nection with the guide means,- a link pivoted at one end upon a stationary axis and at its opposite end to the means carried its stationary axis pivotal support and having operative engagement with the control means forengine control when opera Diesel engine substantially as described. 

